function V = computeV(H)
h1 = H(:,1);
h2 = H(:,2);
v11 = [h1(1)*h1(1),h1(1)*h1(2)+h1(2)*h1(1),h1(2)*h1(2),h1(3)*h1(1)+h1(1)*h1(3),h1(3)*h1(2)+h1(2)*h1(3),h1(3)*h1(3)]';
v12 = [h1(1)*h2(1),h1(1)*h2(2)+h1(2)*h2(1),h1(2)*h2(2),h1(3)*h2(1)+h1(1)*h2(3),h1(3)*h2(2)+h1(2)*h2(3),h1(3)*h2(3)]';
v22 = [h2(1)*h2(1),h2(1)*h2(2)+h2(2)*h2(1),h2(2)*h2(2),h2(3)*h2(1)+h2(1)*h2(3),h2(3)*h2(2)+h2(2)*h2(3),h2(3)*h2(3)]';
V = [v12';(v11-v22)'];
